The present disclosure relates to semiconductors and, more particularly, to structures and methods for forming field-isolated bulk fin field effect transistor (FinFET).
The industry has begun to convert to bulk-based FinFET CMOS recently. One detriment of bulk isolation of the FinFET is the need to dope the fins, and in particular, the sub-fin, which is the region below the gate and between the source and drain. Doping of the sub-fin may be used in order to avoid punch-through leakage. SOI-based FinFETs avoid this problem, but require SOI starting wafers. Techniques to create oxide isolation under a bulk-based FinFET integration also have been demonstrated but are costly and bring other compromises to the devices.